Be careful of the switches. If there's potmetal for the frames, it can become very brittle.
There should be a chassis number on the back. Perhaps a model number stamped on the cabinet somewhere, perhaps under the panel the chassis sits on.
I should have the schematic on hand once we get the chasis number.
A good place to find a match for the model by pictures:
http://www.oldradiozone.com/zenith.html
Schematics:
http://www.nostalgiaair.org/
Lotsa forum help:
http://www.antiqueradios.com/cgi-bin/forums/index.cgi
-Ed (Hoping this helpful reply gets me preferential treatment in your new forum!)